To present this to the courts you are going to have to frame it in terms of mediation. If mediation required something and he failed to hold it up you're going to have to be able to prove that he's done or not done something he was supposed to, so set it up like a list of things he's supposed to do, and then give dates and times that he lapsed in his responsibility.
Hopefully you have documented what visitation dates he has failed to keep. As for not going to N.A. - that may be kind of hard to prove unless you are in the group too. It depends on what state you're in as to whether or not these things will change your custody agreement, but tell the courts your concerns. Who is supposed to administer drug testing? If they haven't called him in for a test there may be nothing you can do in court. It is the responsibility of the testing clinic to notify him when and where he has to submit to tests, and if they aren't doing that you can tell the courts that he needs stricter drug monitoring.
They don't take that into account. My kids' dad offered to pay extra child support to help me pay for day care expenses. The judge turned it down and said day care can be paid out of the amount I am receiving.